Nvidia PureVideo
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NVIDIA's PureVideo is an MPEG-2 decoder designed to offload MPEG-2 decoding work from the CPU and software to NVIDIA's GPU series GeForce 6, GeForce 7, and enthusiast-class GeForce 8. PureVideo is designed to work with Microsoft's Windows Media Player and Windows Media Center. NVIDIA's device drivers for Windows/XP and Windows/Vista are PureVideo-enabled; with the appropriate (PureVideo-enabled) application software, the NVIDIA driver will automatically use whatever hardware-acceleration is available on the NVIDIA display-adapter.
All software HD DVD/Blu-ray players, as well as most software DVD-players, are PureVideo-enabled. The version of Windows Media Player bundled with Windows Vista Ultimate and Home Premium editions (which has a built-in MPEG2 decoder) also supports NVIDIA's PureVideo technology. NVIDIA also sells its own PureVideo decoder software (which is a source of confusion, as NVIDIA's decoder is not required and not used by third-party players), which serves as a DVD-player with advanced post-processing capabilities. The degree of PureVideo's varies by title. Likewise, the level of PureVideo support varies across NVIDIA's product-line, with the mid to high-end products possessing all of PureVideo's benefits, while the budget models are limited to lower-quality or lower-resolution video.
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[edit] PureVideo HD
PureVideo HD (see "naming confusions" below) is a label which identifies NVIDIA products certified for HD DVD/Blu-ray Disc playback, to comply with the requirements for playing Blu-ray/HD DVDs on PC:
- end to end encryption (HDCP) for digital-displays (DVI-D/HDMI)
- realtime H.264 high-profile L4.1, VC-1, or MPEG-2 MP@HL (1080p30) decoding @ 40Mbit/s (Blu-ray Discs only)
- realtime dual-video stream decoding for HD DVD/Blu-ray Picture-in-Picture (primary-video @ 1080p30, secondary-video @ 480p60)
[edit] PureVideo 1
Also known as simply PureVideo. First introduced with the GeForce 6 series, the original PureVideo engine improved upon the GeForce/FX's video-engine (VPE) by adding better deinterlacing algorithms and finer video-resizing for overlays. Compatibility with DirectX 9's VMR9 renderer was also improved. PureVideo inherited the MPEG-2 decoding pipeline from its predecessor, VPE. But in later models of the GeForce 6, PureVideo also offered hardware acceleration for VC-1 and H.264 video, though the degree of acceleration is limited when benchmarked side by side with MPEG-2 video. PureVideo offloads the entire MPEG-2 pipeline excluding run length decoding, variable length decoding, and inverse quantization.[1]
[edit] PureVideo 2
While many PureVideo-capable cards could in fact play downloadable 1080p-video with a sufficiently fast host PC, HD DVD and Blu-ray's specifications push many such systems beyond their limits. In particular, one of the two compression-codes in H.264/AVC high-profile, CABAC, is notoriously unfriendly towards general-purpose CPUs. PureVideo 2 adds a bitstream processor (BSP) and enhanced video processor (VP2) to completely offload AACS-decryption and H.264-decoding. For VC-1 decoding, PureVideo 2 offloads the inverse discrete cosine transform (iDCT) and motion compensation stages, and relies on the host CPU to handle the bitstream processing/entropy stage of the video pipeline.[2]
[edit] Naming confusions
The timing of PureVideo HD and the subsequent PureVideo 2 has led to some confusion. PureVideo HD was originally introduced in 2006, with select models of the GeForce 7 series (7900 series). PureVideo 2-capable hardware did not become available until 2007, with the introduction of the mid-range and value products of the GeForce 8 series. Afterward, the PureVideo HD moniker included both older PureVideo 1-based hardware (GeForce 8800GTS/GTX and all GeForce 7 models), as well as newer PureVideo 2 hardware (GeForce 8400/8500/8600/8800GT). All PureVideo HD products support Blu-ray/HD DVD playback with the proper system components, but PureVideo 2 offers markedly superior acceleration for HD DVD/Blu-ray movies encoded with H.264/AVC.
Also, many NVIDIA cards without the PureVideo HD label are fully capable of playing Blu-ray/HD DVD movies. For example, HDCP-compliance is only mandatory for digitally-connected displays (HDMI/DVI-D). Blu-ray/HD DVD playback to analog displays (VGA/YPbPr) is not affected by the absence of HDCP.
ATI's competing Unified Video Decoder (UVD), is comparable to PureVideo 2 in terms of decoding acceleration. Compared to PureVideo 2, UVD improves VC-1 offloading with dedicated hardware for variable length code decoding. Benchmarks conducted by AnandTech found UVD to outperform PureVideo 2 in VC-1 playback.[citation needed]
[edit] References
- ^ PureVideo: Digital Home Theater Video Quality for Mainstream PCs with GeForce 6 and 7 GPUs (PDF) p. 9. Nvidia. Retrieved on 2008-03-03.
- ^ PureVideo Support table (PDF). Nvidia. Retrieved on 2007-09-27.
[edit] See also
AVIVO - A competing technology from ATI for use with their video cards.
[edit] External links
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